Water, gas, electricity, steam and the like as well as associated pipes, conduits and cables when associated with a building are often referred to collectively as the "utilities". In the process of construction, it is standard for walls and floors of a building to be built and later penetrated for the utilities to be installed. This method of construction normally means that the walls will be breached with a series of holes that are somewhat larger than the utility conduit to be installed. This size discrepancy is both an expedient method, from the standpoint of labor utilization, and a necessary variance because the utility conduit may be of a different size from the available standard sizes of hole making apparatus. Once such a hole is made and a conduit or a number of conduits are passed through, the gap remaining around the conduit or conduits provides a passage through which, in the event of a building fire, flame and smoke may be transmitted from one room to another, increasing damage and injury.
When the walls are constructed of materials which are able to contain a fire for a period of time, such a wall-breaching hole will void the value of the wall's fire retardancy. Much effort has been expended toward eliminating these wall-breaching holes, and thus containing a fire to a single room in a building. Underwriters Laboratories, Inc. has developed a Fire Resistance Directory, a section of which is devoted to Through-Penetration Firestop Devices, beginning on page 1252. A number of known devices and methods are listed therein. Included in the standard materials known in the industry and identified in the Directory are thermo-expansive, or intumescent, materials. The intumescent material referred to in the Directory and as used herein is initially activated to expand when the material reaches a temperature of about 150.degree. C. (300.degree. F.), and it expands to between 5-15 times its original volume.
In addition to the Underwriters Laboratories, Inc. Directory, the Minnesota Mining and Manufacturing Company (3M) provides a catalog of fire prevention products. Included in the 3M product grouping are intumescent materials which are supplied in the form of caulking and flexible strips. 3M also advertises a collar, taught in U.S. Pat. No. 5,103,609 to Thoreson et al. as an Intumescent Fire Stop Device. The '609 patent discloses a collar adapted to be installed around a utility conduit at the point of wall-penetration and having an intumescent lining and heat conducting tabs. The collar also includes wall-attachment tabs.
A further United States Patent directed to the field of the invention is U.S. Pat. No. 5,155,957 to Robertson et al. for a Fire Safety Device. The device of the '957 patent is adapted for closing through-holes in floors and walls and for stopping the potential spread of fire and smoke. The '957 device includes a section of conduit, a cup-shaped retainer and a quantity of intumescent material.
The above discussed devices and others known in the trade are able to provide a degree of fire and smoke protection, but are somewhat dependent on installer skill or do not afford the effectiveness provided by the present invention.
It is therefore an object of this invention to provide a fire and smoke blocking system to seal wall-breaching holes in a building wall or floor.
It is another object of this invention to provide a fire and smoke blocking system which is simple to install in a formed hole.
It as an additional object of this invention to provide a fire and smoke blocking system which will maximize the sealing of a wall-breaching hole in case of a fire.
Other objects and advantages will be more fully apparent from the following disclosure and appended claims.